With areaportal problems, it's almost always caused by one of the areaportals not fully touching the surrounding world geometry. Or somehow one of the areaportals brushes is no longer a func_areaportal. For example, if you had "solids" selected instead of "objects" and copied the areaportal, it'd just become a brush without func_areaportal.

You can also get problems if two different areaportals are lined up. Like two different doors on the same wall. Shift one slightly forward and one slightly back within the doorframe to avoid that.

The pointfile never seems very accurate for areaportal problems even though it's perfectly accurate for normal leaks.

What I do is turn EVERYTHING off except for world geometry and skybrushes. Displacements, props, everything. Then turn on just the areaportal brushes and go in and inspect the edges of each and every one individually for gaps.

I also name my areaportals ap0, ap1, ap2, etc so if VBSP catches the leak, it'll spit out the name of the specific areaportal that has a problem: "Brush ap02: areaportal brush doesn't touch two areas." You can remove the names later after areaportals are working correctly; I think removing the names might reduce the ent_data slightly but I'm not 100% positive.

If there is an areaportal leak they will follow the path of the areaportals where they leak. There are a few exceptions when the areaportal itself is not correctly placed inside a doorway (instead of 2 sides it has 3 or more) and it decides to randomly point to an area. This could also be the case you have. And the worst part being that it might not even show the portal that is being the cause

Then there is the problem that 2 areaportals acros the map are on the same line. they get merged. And this happens even acros the map which again can give problems.

To debug the portals select all of them on 1 side and put them in a visgroup. hide it. Then compile. No error. Do the same to the other side. If it works seperately it has to do with 2 portals on each side which most likely got merged. if only 1 side is broken repeat the steps on that side until you are left with only 1, 2 or 3 portals.